The present invention generally relates to laser systems and more particularly to a laser amplification system.
It is known to employ chirp pulse amplification (“CPA”) for ultrashort lasers. Chirping overcomes concerns with intense ultrashort laser pulses inducing nonlinear optical processes in transparent media which would otherwise damage the amplification equipment. When chirp pulse amplification is used, the pulses are stretched by a factor greater than 1000 and therefore their intensity is significantly reduced. Examples of chirp pulse amplification can be observed in the following U.S. Pat. Nos. 5,862,287 entitled “Apparatus And Method For Delivery Of Dispersion Compensated Ultrashort Optical Pulses With High Peak Power” which issued to Stock et al. on Jan. 19, 1999; 5,633,885 entitled “Frequency Chirp Control And Compensation For Obtaining Broad Bandwidth Ultrashort Optical Pulses From Wavelength-Tunable Lasers” which issued to Galvanauskas et al. on May 27, 1997; and 5,572,355 entitled “Optical System For Stretching, Compressing And Amplifying Ultrashort Optical Pulses” which issued to Cotton et al. on Nov. 5, 1996; all of which are incorporated by reference herein. Chirp pulse amplification, however, requires an expensive set of optics.
An experiment has also been conducted which provides one SLM pulse shaper before a regenerative amplifier and another SLM pulse shaper after the amplifier. This experiment is disclosed in I. Pastirk, B. Resan, A. Fry, J. Mackay and M. Dantus, “No Loss Spectral Phase Correction and Arbitrary Phase Shaping of Regeneratively Amplified Femtosecond Pulses using MIIPS,” Optics Express, Vol. 14, No. 20, 9537 (2006). CPA amplifiers, having a large stretcher and compressor, were used in this experiment. Furthermore, symmetric and single binary phase step functions were used and only for multiphoton intrapulse interference phase scan purposes in the chirped pulse.
In accordance with the present invention, a laser amplification system is provided. In another aspect, a laser system and method include at least one optic member operably introducing a phase function into a high peak intensity laser pulse. A further aspect includes introducing destructive nonlinear optical interference in an unchirped laser pulse prior to amplification and reconstructive interference in the output laser pulse after amplification. Dynamic pulse shaping is employed in an aspect of the present system. In yet another aspect, a minimal correlation binary phase function is introduced into a laser pulse prior to amplification.
The present laser system is advantageously less expensive and more efficient than traditional chirped devices. The present laser system is also more compact and is less sensitive to air turbulence as compared to conventional chirped devices. Moreover, the present system maintains a more intense pulse but without harmful nonlinear optical processes therein. Additional advantages and features of the present invention will become apparent from the following description and appended claims, taken in conjunction with the accompanying drawings.